Loud-speaker



June 11, 1929. w, KUNZE 1,716,893

LOUD SPEAKER Filed July 25, 1928 f 2 Sheet's-Sheet l Wilbur/ll June 1l, 1929. w. KUNZE 1,716,893

LOUD SPEAKER Filed July 25, 1928 2 Sheets-Sheet 2 Patented June 11, 1929.

' UNITED STATI-:S

WALTER XUNm, F BERLIN-WANNSEE, GERIANY.`

LOUDLSPEAKEB.

Application led July 25, 1928, Serial No. 295,272, and in Germany July 30, [1927.'

A type of loud speaker which gives good results is one in which a vibrating reed is operated by variations of a magnetic system or field corresponding in a measure to `l that of a polarized relay in which it is placed and in which it is influenced by both the flux of the permanent magnet and the alternating flux generated by the currents to be reproduced. Owing to the fact, however, that the reactions are not centralized, for the reason that the reed is supported solely from one side of the system, such a loud speaker responds most strongly to a certain frequency, that is, to a limited resonant frequency, and is subject to reproducing imperfections due to its mode of support. Attempts have been made to overcome this difficulty and to provide for the support of the reed from both sides of the field, in order to secure centralized reactions, greater intensity, a

greater frequency range, and a morel faithul reproduction, but, so far as I am aware, these attempts have been without practical success.

One object of my invention is to provide a loud speaker employing a vibratory reed in which the reed is supported from both sides of the magnetic s stem and arranged so that the reactions of t e magnetic field are centralized and transmitted to the working diaphragm in such manner as to obtain a wide frequency range, and greater intensity and a much more faithful reproduction of the signals. A further object of the invention is to provide means whereby the sensitiveness of action of the reed may be regulated and the resonant frequency of the speaker varied within desirable limits.

The invention consists of the features of construction, combination and arrangement of parts, hereinafter fully described and claimed, reference being had'to the accompanying drawings, in which Figure l is a front elevation of one form of loud speaker embodying my invention.

Figure 2 is a similar view showing a modification.

Figure 3 is a similar view showing another modification.

Figures 6 and7 are views showing details of construction of the device illustrated in Figures 4 and 5.

Referring now more particularly to Figure 1 of the drawing,"A, A designate a palr of superposed permanent magnets, preferably of horseshoe type, and having the pole pieces C, C carrying the field coils D, D. A reed B is clamped at one end at the side of the magnets opposite the ole pieces between the magnets and exten s across the field space between the limbs of the magnets with its free end arranged'to vibrate in the gap between the pole pieces C, C. Extending across the field space of the magnets and secured to the limbs thereof at opposite sides of said field space is a bridge E of non-magnetic material. Centrally of the field of the magnets is arranged a stem F which couples both the reed B and the non-magnetic bridge E to the working diaphragm Q, of the loud speaker, which may be of conical or other type. The stem F is threaded to receive securing and adjusting nuts f whereby the reed and the bridge are secured to the stem and whereby adjustment is afforded to regulate the position of the free end of the reed in the gap between the pole pieces to regulate the sensitiveness of action of the reed and to vary within certain degrees its resonant frcquency. With this arrangement it will be seen that the reactions of the field are centralized for transmission to the working diaphragm so that a high degree of efficiency of the action of the reed is obtained to secure greater intensity of sound and a more faithful reproduction of the signals received.

In Figure 2 a modified form of the invention is shown in which there is substituted for the two field coils D, D a single field coil H of larger size, and in which the pole piece T extending through the coil is of larger dimensions than the pole piece K. The reed L in this instance is secured at one end by a screw M to the magnets at one side and' provided adjacent to its secured end 100 with a more or less resilient offset portion iM carrying an adjusting screw M2 bearing against one of the magnets whereby the position of the reed in the gap between the pole pieces may be regulated and the resistance to vibration of the reed governed. Also in this construction the non-magnetic bridge E is rigidly secured to the magnets at one side of the field by fastening means E2, while the opposite end of the bridge is free from connection with the magnet and pro-l at the opposite side of the field whereby the tension of the bridge and its resistance to vibration may be regulated. By means of these adjustment features the action of the reed may be sensitively controlled, as well as the sensitiveness of action of the bridge, and the pitch and frequency of the speaker varied within determined limits.

In Figure 3 ofthe drawing another modified form of the device is shown in which the structure is Asimilar to that shown in Figure l with the omission of the lower magnet A and the pole piece C and coil D. The elements in this construction corresponding to those in Figure l are indicated by the same reference characters. This construction provides a simplified type of single magnet unit which may be inexpensively manufactured and at the same time gives good results.

InFigures 4 to 7 inclusive, still another modified form of the invention is shown in which a single magnet A, a pole piece C2 and a field coilD2 are employed. In this construction, however, the reed B isarranged at the top of the magnet and secured at one end to one of the magnet lilnbs and extends at an oblique angle across the field space with its free end arranged for coaction with the pole piece C?. The nonmagnetic bridge E4 in this construction is arranged at the base of the magnet and extends across thc field space thereof and is secured at its opposite ends by fastenings E5 to the opposite limbs of the magnet. Preferably the bridge is arranged at an oblique angle so as to cross the reed, whereby a centralized coupling arrangement is provided for and the use of a comparatively long bridge obtained so that a maximum degree of efficiency is secured. In this construction of device provision is made for regulating the distance between the reed and pole piece and the sensitiveness ofl action of the reed so that the resonant frequency may be varied. As shown, the reed B is fastened to the stem F which is adjustable and elastically coupled to the bridge E4 by a coiled spring F2. This spring is fastened at one end to the stem F and at its opposite end is clamped by a nut F3 to a threaded regulator stem I having a flattened side or being of non-circular form and slidably and non-rotatably moveable through a similarly shaped opening I2 in the non-magnetic bridge. The rod or stem I is in threaded engagement with an adjusting sleeve J having an annular groove 7' engaged by the fork ends of bearing plates j secured to the bridge whereby the sleeve is swiveled to rotate and held from longitudinal movement. The sleeve J carries a knob or other operating member J whereby it may be rotated to advance or retract the stem I and thereby compress the spring F2 or permit it to. expand, by means of which the distance between the reed and the pole piece may be varied and the sensitiveness of action of the reed governed and the resonant frequency of the speaker varied within desirable limits.

Figure 5 shows a convenient way of arranging a condenser O in parallel with the magnet coils by mounting the same upon a support P of insulating material upon the unit itself. A

In all the constructions disclosed it will be observed that the arrangement is such as to provide for the transmission of the field reactions to the working diaphragm in the most effective manner and so that great intensity and vitality of reproduction may be obtained.

What I claim is 1. A loudspeaker comprising means for producinga magnetic field, a vibratory reed secured at one end at one side of said field and extending across the field and having its opposite end lying adjacent to the opposite side of the field, a diaphragm, and a nonmagnetic element extending across and fixed to both sides of the field, said element being coupled to the diaphragm and to the reed between the secured and free ends of the latter.

2. A loudspeaker comprising means for producing a magnetic field, a vibratory reed secured at one end at one sideof said field and extending across the field and having its opposite end lying adjacent to the opposite side of the field, means for adjusting the reed with respect to the field zone with which it directly coacts, a diaphragm, and a nonmagnetic element extending across and fixed to both sides of the field, said element being coupled to the diaphragm and to the reed between the secured and free ends of the latter.

k3. A loudspeaker comprising means for producing a magnetic field, a vibratory reed secured at one end at one side of said field and extending across the field and having its-opposite end lying adjacent to the opposite side of the field, a diaphragm, a non-magnetic element extending across and fixed to both sides of the field, said element being coupled to the diaphragm and tothe reed between the secured and free ends of the latter, and means for varying the tension of the non-magnetic element.

4. A loudspeaker comprising means for producing a magnetic field, a vibratory reed secured at one end at one side of said field and extending across the field and having its opposite end lying adjacent to the opposite side of the field, a diaphragm, a non-magnetic element extending across and fixed to lli both sides of the ield, said element being coupled to the diaphragm and to the reed between the secured and free ends of the latter, and means for adjusting the reed and non-magnetic element to regulate the action thereof.

5. A loudspeaker comprising a permanent magnet, a reed secured at one end at one side ofthe magnet and having its free end vibrating between the pole pieces of the magnet, a diaphragm, and a non-magnetic bridge secured to the magnet at both sides thereof and coupled to the reed and the diaphragm.

6. A loudspeakercomprising a permanent magnet, a reed secured at one end at one side of the magnet and having its free end vibrating between the pole pieces of the magnet, means for adjusting the reed with relation to the pole pieces, a diaphragm, and a nonmagnetie bridge secured to the magnet at both sides thereof and coupled to the reed and to the diaphragm.

7. A loudspeaker comprising a permanent magnet, a reed secured at one end at one side of the magnet and having its free end vibrating between the pole pieces of the magnet, a diaphragm, a non-magnetic bridge secured to the magnet at both sides thereof and coupled to the reed and to the diaphragm, and means for varying the tension ofthe bridge.

8. A loudspeaker comprising a permanent magnet, a reed secured at one end at one side of the magnet and having its free end vibrating between the pole pieces of the magnet, means for adjusting the reed with relation to the pole pieces, a diaphragm, a non-magnetic bridge secured to the'magnet at both sides thereof and coupled to' the reed and to the diaphragm, and means for varying the tension of the non-magnetic bridge.

In testimony whereof I aix my signature.

WALTER KUN ZE. 

